Semiconductor packages are commonly used to house and protect integrated circuits, such as microprocessors, power transistors, amplifiers, controllers, ASIC devices, sensors, etc. A common configuration of a semiconductor package includes a metal substrate, i.e., a “die pad,” that is centrally located within the package, and a plurality of electrically conductive leads that are spaced apart and extend away from the substrate. A semiconductor die (or dies) is mounted on the substrate by solder or adhesive, for example. The semiconductor die includes conductive bond pads on its upper surface. These conductive bond pads provide the input output terminals of the semiconductor die. An electrical connection is provided between the bond pads and the package leads. An encapsulant material seals and protects the semiconductor die and the electrical connections from moisture and dust particles. The ends of the leads are exposed from the encapsulant material and thus provide externally accessible terminals for the packaged device.
There are several techniques for electrically connecting the bond pads of the semiconductor die to the package leads in semiconductor packages. For example, one common technique is a wire bonding technique wherein one or more bond wires are bonded to each bond pad and to the package leads. One drawback of a wire bonding technique is that the wire bonding process may damage the bond pads. Another drawback of a wire bonding technique is that minor variations in wire bond loop height and length, which are difficult to control, can cause significant variation in the electrical behavior (e.g., inductance) of the electrical connection. For these reasons, metal clips have gained favor over bond wires in certain applications. Metal clips are typically metal structures that are specially designed for placement on the bond pad and leads so as to provide an electrical connection between the two. Metal clips offer improved electrical performance (e.g., lower resistance, better current distribution, etc.), as they are substantially wider and thicker than typical bond wires.
Designers are constantly seeking ways to improve the performance of packaged semiconductor devices. In particular, designers are seeking to improve the electrical performance and reliability of the electrical connections between the semiconductor die and package leads.